If you have an Applol computer with Safari as your browser and haven't updated flash in a while you will need to do that manually since Adobe's piece-of-crap self-updater basically doesn't work at all, causing the browser addon to get blocked due to being old and outdated.
Haven't ever seen flash auto-update despite the option having been there for years now. It's amazing how fucking incompetent a company can get and still remain in business, and Adobe's one of the worst who haven't managed to bankrupt themselves with their own ineptitude.